Polarization device, polarization plate and video display device having superior durability and heat resistance

Abstract

Provided are polarizer, polarizing plate, and image display device having excellent durability and heat resistance in which contents of zinc, boron, and iodine in the polarizer are controlled in a specific range. According to an embodiment of the present invention, a polarizer having a value of zinc content (wt %)×boron content (wt %)/iodine content (wt %) in a range of about 0.1 to about 3.0 in all positions in which a depth (D) from a surface to a center of the polarizer is 0≦D≦200 nm, polarizing plate and image display device including the polarizer are provided. The polarizer, polarizing plate, and image display device according to the present invention have excellent durability and heat resistance in which initial cross transmittance and color are maintained and transmittance, degree of polarization, and color are maintained even under high temperature conditions.

1 . A polarizer having a value of zinc (Zn) content (wt %)×boron (B) content (wt %)/iodine (I) content (wt %) in a range of about 0.1 to about 3.0 in all positions in which a depth (D) from a surface to a center of the polarizer is 0≦D≦200 nm. 
     
     
         2 . The polarizer of  claim 1 , wherein zinc is derived from at least one selected from the group consisting of zinc chloride, zinc iodide, zinc sulfate, zinc nitrate, and zinc acetate. 
     
     
         3 . The polarizer of  claim 1 , wherein boron is derived from at least one selected from the group consisting of boric acid, borate, and borax. 
     
     
         4 . The polarizer of  claim 1 , wherein iodine is derived from at least one selected from the group consisting of iodine (I 2 ) and potassium iodide. 
     
     
         5 . The polarizer of  claim 1 , wherein the value of Zn content (wt %)×B content (wt %)/I content (wt %) in all positions in which the depth (D) from the surface to the center of the polarizer is 0≦D≦200 nm is obtained by using an electron spectroscopy for chemical analysis (ESCA) method through etching the polarizer at about 0.1 nm/sec to a maximum depth of about 200 nm for about 2000 seconds. 
     
     
         6 . A polarizing plate comprising the polarizer of  claim 1 . 
     
     
         7 . An image display device comprising the polarizer of  claim 1 . 
     
     
         8 . A polarizing plate comprising the polarizer of  claim 2 . 
     
     
         9 . A polarizing plate comprising the polarizer of  claim 3 . 
     
     
         10 . A polarizing plate comprising the polarizer of  claim 4 . 
     
     
         11 . A polarizing plate comprising the polarizer of  claim 5 . 
     
     
         12 . An image display device comprising the polarizer of  claim 2 . 
     
     
         13 . An image display device comprising the polarizer of  claim 3 . 
     
     
         14 . An image display device comprising the polarizer of  claim 4 . 
     
     
         15 . An image display device comprising the polarizer of  claim 5 .